1. Field of the Invention
The present invention relates to a method, apparatus and computer program product providing a mechanism for providing aggregate information used for interference considerations in multi-carrier or multi-component carrier systems, in particular with regard to uplink direction.
2. Related background Art
the following meanings for the abbreviations used in this specification apply:
3GPP—3rd generation partnership project
ACCS—autonomous component carrier selection
BIM—background interference matrix
CC—component carrier
DL—downlink
eNB—enhanced node B (LTE base station)
HeNB—home eNB
IoT—interference over thermal noise
IP—Internet Protocol
LTE—Long Term Evolution
LTE-A—LTE-advanced
PCC—primary component carrier
PSD—power spectral density
RRAT—radio resource allocation table
RSRP—reference signal received power
RSRQ—reference signal received quality
SCC—secondary component carrier
UE—user equipment
UL—uplink
URLM—uplink radio load map
In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) communication networks like the Universal Mobile Telecommunications System (UMTS), cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolutions (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN) or Worldwide Interoperability for Microwave Access (WiMAX), took place all over the world. Various organizations, such as the 3rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments.
Generally, for properly establishing and handling a communication connection between network elements such as a UE and another communication equipment, such as a database, a server, etc., one or more intermediate network elements, such as base transceiver stations, network control elements, support nodes, service nodes and interworking elements are involved which may belong to different communication networks.
In particular in wireless communication networks, it is important to use the available limited resources, in particular with regard to bandwidth, channel capacity etc. as good as possible so as to achieve a good balance between provided service or connection quality and degree of capacity utilization. In order to achieve this, substantial planning and simulation efforts are taken so as to ensure that a deployed network infrastructure is able to provide good service performance and to minimize interference issues, and the like.
One new approach to further develop telecommunication networks is the installation of so-called low-power base stations, which are also commonly referred to as “femto-cells” or home eNB (HeNB). Such low-power base stations are advantageous in that they are low-cost and possibly user-deployed cellular base stations offering higher capacity per area as compared to macro cells, arising from using smaller cell sizes and more efficient spatial reuse. According to current considerations, as done for example by 3GPP, corresponding low-power base stations or HeNBs may appear like a normal (macro cell) base stations (for example like an eNB) for UEs so that there are no changes necessary in the UEs.
However, despite the benefits achievable by installing such HeNBs, there may arise also problems which have to be considered for guaranteeing proper functioning of telecommunication networks. For example, issues regarding interference management and efficient system operation are to be considered.
Uncoordinated deployments of eNBs (such as HeNBs) in local area environments can benefit from having support for dynamic frequency re-use mechanisms. Such schemes are based on a mechanism where each base transceiver station, such as an eNB or a HeNB, dynamically selects to use only a subset of the available component carriers (i.e. using from one component carrier up to the maximum number of available component carriers). Examples for such schemes planned to be used, for example, in LTE or LTE-A network systems are referred to, for example, as “autonomous component carrier selection” (ACCS) or “dynamic management of frequency band resources”. In the following, a corresponding scheme will be referred to as ACCS.
The ACCS scheme provides an automatic and fully distributed mechanism for dynamic frequency re-use on a component carrier resolution. In principle, each component carrier is eligible for use in any cell. However, for this purpose, it has to be ensured that certain signal to interference plus noise ratio (SINR) constraints are satisfied.
Thus, in order to ensure the long-term ‘quality’ of the radio link on a component carrier allocated to or used by a base transceiver station (i.e. a maximum tolerable inter-cell interference) and minimize its reconfiguration frequency as much as possible while still providing full cell coverage, certain radio monitoring and CC recovery procedures are required. These procedures have to be performed for both DL and UL traffic on the component carrier.
However, it has been found out that in particular for the UL traffic, the aggregation and processing of information usable for a detailed and useful interference analysis are difficult. This is, for example, due to the distributed nature of the interference, originating from all the UEs served by neighboring base transceiver stations, such as eNBs. Specifically, the identification (ID) of such UEs are known only in their own serving eNBs. Due to a limited signaling between eNBs, detailed per-UE information may be prevented to be exchanged in the entire network of deployed eNBs. Thus an UL interference characterization is in general difficult to achieve and can only be based, for example, on additional but limited information exchange between eNBs.